Figure 1: Authentication Flowchart This figure shows the authentication process. The switch reauthenticates a client when one of these situations occurs: • Periodic reauthentication is enabled, and the reauthentication timer expires. You can configure the reauthentication timer to use a switch-specific value or to be based on values from the RADIUS server. After 802.1x authentication using a RADIUS server is configured, the switch uses timers based on the Session-Timeout RADIUS attribute (Attribute[27]) and the Termination-Action RADIUS attribute (Attribute [29]). The Session-Timeout RADIUS attribute (Attribute[27]) specifies the time after which reauthentication occurs.
The range is 1 to 1073741823 seconds. Note In releases prior to Cisco IOS XE Bengaluru 17.5.1, the supported timeout range is 1to 65535. seconds. While downgrading from or releases after Cisco IOS XE Bengaluru 17.5.1 set the timeout to supported values to avoid ISSD breakage. seconds. While downgrading from or releases after Cisco IOS XE Bengaluru 17.5.1 set the timeout to supported values to avoid ISSD breakage. Configuring IEEE 802.1x Port-Based Authentication Port-Based Authentication Process Configuring IEEE 802.1x Port-Based Authentication 4